Completeness Before Certainty: Evidence Paradoxes in the First EU Joint Clinical Assessments

The EU Health Technology Assessment Regulation makes the joint clinical assessment dossier the foundation of a single European appraisal of the relative effectiveness and safety of new medicines, and Article 9 conditions that foundation on the completeness of the evidence a developer submits. Drawing only on the first publicly observable outputs of the new system — two completeness reviews and one completed assessment — this article asks how the European Commission and the HTA Coordination Group are giving operational meaning to “completeness”. It argues that an exacting interpretation is emerging, closer to the logic of systematic review than of regulatory submission, but that the evidentiary base remains too thin to call it a settled doctrine. Two structural tensions follow: a certainty paradox, in which uncertainty is catalogued exhaustively yet never converted into a graded judgment of certainty; and an evidence-generation paradox, in which developers of orphan and highly innovative therapies may face analytical demands whose outcome is largely foreseeable. The article situates these tensions within the principle of proportionality, the duty to give reasons and the limits of judicial review, and sets out a research agenda for the Regulation’s scheduled 2028 evaluation.